1) Field of the Invention
The present invention relates to an apparatus for handling structural members and, more particularly, relates to an apparatus for releasably engaging and moving structural members into and out of a processing device such as a superplastic forming hot press.
2) Description of Related Art
The manufacture of a structural member often includes forming and treating the structural member in a number of different processing devices, each requiring the structural member to be lifted and loaded into the device and subsequently lifted and unloaded from the device. Often such handling of the structural member is performed at least partially by an operator. For example, an operator might load an unprocessed structural member into a processing device by lifting the structural member from a stack of available structural members that are waiting to be processed, loading a structural member onto a processing platform such as a die, and aligning the structural member with one or more guides on the platform. Repeated loading in this fashion can be fatiguing to the operator, especially if the structural members are heavy, large, or otherwise difficult to handle. For example, structural members formed in a superplastic forming hot press can weigh 150 pounds or more and can be several feet long and several feet wide. In order to load and unload the structural member horizontally on the processing platform, the operator must lean over the structural member, further increasing the difficulty loading and unloading and further increasing fatigue.
The handling of the structural member is made more difficult if human contact with the structural member is undesirable. If the structural member is hot, sharp, toxic, or otherwise dangerous, the operator may be required to wear protective gear while handling the structural member and/or limit the duration of interaction with the structural member. For example, structural members formed in a superplastic forming hot press may be heated to temperatures exceeding 1700xc2x0 F. for forming. The structural members may be preheated before loading into the press and can emerge from a press at temperatures as high as the forming temperature. Operators that load and unload structural members directly into and out of such a hot press must wear temperature protective clothing, which often is uncomfortable, limits the manual dexterity of an operator, and inhibits the operator""s vision and other senses. Additionally, an operator may be required to use special handling techniques to limit exposure to the heat from the structural members and the press. For example, lifting the structural member from the press may require an operator to quickly lean over the press, grasp the structural member, lift the structural member, move to a cooling area, and lower the structural member. The operator must work quickly to avoid excessive heat exposure.
Alternatively, an operator can use a lifting mechanism, such as an overhead crane or winch to provide the lifting force necessary to load the structural member. In that case, the operator attaches the crane to the unprocessed structural member, for example, by using hooks to connect a cable between the structural member and the crane. The operator then uses the crane to lift the structural member and hold the structural member in an elevated position while the operator then grasps the structural member and moves it to a position above the processing platform. The operator then lowers the structural member with the crane, removes the hooks from the structural member, and adjusts the placement of the structural member to align the structural member relative to the processing platform. The crane reduces the lifting stress on the operator, but still requires the operator to work near the hot structural member to connect the structural member to the crane, move the structural member, disconnect the structural member from the crane, and adjust the alignment of the structural member.
One device that has been proposed for handling structural members includes a scissoring linkage that can be extended and retracted vertically by a pneumatic actuator. The scissoring linkage is supported from above such that extension and retraction of the linkage raises and lowers a fork. The fork is connected to the structural member using a long rod that is threaded horizontally through at least one aperture on each of the fork and the structural member. Similar to the crane described above, the pneumatic actuator provides the lifting force for loading and unloading the structural member. However, the operator must still work near the structural member and the processing device to connect and disconnect the fork and the structural member and to move the structural member to and from the platform. Also, threading the long rod through the fork and structural member requires the various apertures to be closely aligned. Threading is made difficult if the structural member or the fork is out of alignment, for example, due to deflection of one or more components or incorrect placement of the scissoring linkage by the actuator. One or more operators may be required to manually push the fork and/or structural member into alignment. Additionally, because the pneumatic actuator is not capable of precise placement of the structural member, the operator must manually assist the placement of the structural member on the processing platform so that it is not damaged during placement and manually align the structural member relative to the processing platform. The operator is at significant risk of fatigue.
Thus, there exists a need for an apparatus for handling a structural member. The apparatus should be capable of lifting, moving, and manipulating structural members without requiring significant physical exertion on the part of the operator. The apparatus should also be capable of engaging and precisely placing the structural member without requiring the operator to work close to the structural member or the processing device, thus reducing the operator""s exposure to heat and/or other dangers. Preferably, the apparatus should be compatible with different structural members.
The present invention provides an apparatus for handling structural members. According to one embodiment of the present invention, the apparatus includes a beam extending from a first end to a second end, a shuttle in translational communication with the beam in a direction extending between the first and second ends, a fork actuator connected to the shuttle, and a fork connected to the fork actuator.
According to one aspect of the present invention, the beam is rotatable about a vertical axis. For example, the beam can be cantilevered from a hinge. A beam actuator can communicate with the beam and rotate the beam about the vertical axis.
According to another aspect of the invention, a plurality of wheels are rotatably connected to the shuttle and in rolling contact with the beam to translatably engage the beam to the shuttle so that the shuttle can be translated along at least a part of the beam, for example, by a shuttle actuator. The beam can define a rack gear extending between the first and second ends of the beam and each wheel of the shuttle can define teeth that engage the rack gear.
The fork actuator has a first portion and a second portion, which can be hydraulically raised and lowered. The fork is connected to the second portion so that the fork is raised and lowered therewith. According to one aspect of the invention, an extension lock engages the fork to the first portion of the fork actuator and thereby prevents extension of the fork. A rotational actuator such as a variable speed electric motor can rotate the fork actuator relative to the beam.
According to yet another embodiment of the present invention, the fork has a first end and a second end. The first end is connected to the fork actuator and the second end extends outwardly from the fork actuator such that the second end is capable of extending outwardly into a heating chamber to engage the structural member. The fork can also include a latch linkage, a latch actuator capable of adjusting said latch linkage, and at least one latch member. The latch linkage is adjustable to releasably engage the latch members with the structural member. For example, the latch linkage can include one or more pushrods that slidably engage the fork and latch members such as latches that are rotatably connected to the fork and the pushrods. Translation of each pushrod causes a respective latch to engage and disengage the structural member.
According to still another embodiment of the invention, the fork includes a cooling system such as passages for circulating a coolant. The passages can extend between the first and second ends of the fork and can be fluidly connected to a coolant source. Additionally, the apparatus can include a duct connected to the fork and configured to emit a cooling fluid directed toward the structural member when the fork is engaged to the structural member.
The present invention also provides an apparatus for releasably engaging and handling a heated structural member. The apparatus includes a tubular structure extending longitudinally from a first end to a second end and defining at least one passage for circulating a coolant. At least one pushrod is movably engaged with the tubular structure, and an actuator is capable of adjusting the at least one pushrod relative to the tubular structure. A controller is in remotely operable communication with the actuator such that adjustment of the controller adjusts the at least one pushrod. Further, at least one latch is rotatably connected to the tubular structure and at least one of the pushrods so that translation of each pushrod causes a respective latch to engage and disengage the structural member.
According to one aspect of the invention, a liquid coolant source is fluidly connected to the at least one passage. According to another aspect, a duct is connected to the tubular structure and configured to emit a cooling gas directed toward the structural member when the latch is engaged to the structural member.
Thus, there is provided an apparatus for handling a structural member. The apparatus is capable of lifting, moving, and manipulating structural members and does not require significant physical exertion by the operator. Also, the apparatus is capable of engaging and precisely placing a variety of different structural members so that the operator does not need to work close to the structural member or the processing device, thereby reducing the operator""s exposure to heat or other dangers.